Bonded Seals (US, USS) are metal rings with a trapezoidal elastomer sealing lip fixed to the inside diameter.
US standard type with vulcanized elastomeric sealing lip on the inside
USS standard type with vulcanized elastomeric sealing lip on the inside and extra centering ring
Material: Elastomeric sealing lip NBR, NB 70, Elastomeric sealing lip FKM FP 70 black
Color: NBR 70, black; FKM 70, brown
Metal ring: Standard steel SAE 1008 (1.0330), Rust and acid-resistant steel SAE 304 (1.4301)
Surface protection metal ring standard steel with zinc chromed (Cr VI free)
Color: Silver gray
Temperature NBR: -30 ° C to + 100 ° C
Temperature FKM: -15 ° C to + 200 ° C
The maximum pressure in operation depends on the type of seal, the material, the size, the sealing surface and the force with which the bolt is tightened. Bottom seal rings are suitable for unevenness in the sealing surfaces
max. 25 MPa pressure.
Rmax ≤ 15 µm
Ra ≤ 3.2 µm
By tightening the bolts, the elastomer sealing lip is compressed and thus ensures the sealing function on the surfaces to be sealed. The sealing lip prevents leakage, preventing pressure loss. In addition, the sealing lip provides protection against dirt from outside. The centering on the USS type ensures that when the bolts are tightened the rings are fixed in the correct position and also ensures easy assembly.
Washers are used as a static seal for bolts and flange seals, e.g. in machine construction and in the construction of reservoirs and general equipment construction.
Advantages of the bottom seal ring
- Easy assembly
- Guaranteed seal
- Fixing ring by self-centering
- Affordable (cheap) solution
- Controlled compression by the metal disc
- Available in various metal versions
- Available for almost all European thread sizes
Medium resistance of the elastomeric sealing lip
Good chemical resistance to mineral oils and fats, hydraulic oils H, HL, HLP, HFA, HFB, HFC, flammable liquids up to approx. 50 ° C and water up to max. 80 ° C.
Good chemical resistance to mineral oils and fats, synthetic oils and fats, engine, cardan and ATF oils up to approx. 150 ° C, motor fuels, HFD, flammable liquids, aliphatic, aromatic and chlorinated hydrocarbons, water up to 80 ° C, very good weather, ozone and aging resistance, allows little gas to pass through (therefore suitable for vacuum applications), very resistant to chemicals.
Other special types such as underlay seals with the vulcanized elastomeric sealing lip (type UA) on the outside or according to the customer's drawing are available on request. Other elastomeric materials such as EPDM, HNBR and FVMQ are also available upon request. We can also supply the metal ring in various special steels such as, for example, SAE 316 (1.4401) or SAE 316TI (1.4571), to ensure better rust and acid resistance.
A bonded seal is a static seal that is used for sealing bolt heads, nuts, screw couplings and flange connections. The seal consists of a metal ring with a fixed rubber part.
The bonded seal is known by various names, among others;
- Usit ring
- Dowty seal
- Dyna seal
APPLICATION OF THE SEAL
Bonded seals are used as a seal under a coupling. They are used in particular in high-pressure systems where copper rings are not suitable. The bonded seal is resistant to high pressures through the metal ring. This prevents deformation of the (vulcanized) rubber element. With the correct assembly, the bonded seal can be reused multiple times.
SELF-CENTERING BONDED SEAL
In addition to the standard bonded seal, Techniparts also supplies a self-centering version. This is applied at higher pressures. The self-centering version has an extra centering edge: a lip on the inner diameter of the rubber ring. This has the same diameter as the core diameter of the screw thread. This centers the seal, holds it in place and prevents leakage. In addition, the self-centering bonded seal has the advantage that it can be mounted very easily.
Bonded seals can be made in various materials. Options include:
Galvanized steel or stainless steel.
tandard NBR. If NBR is not satisfactory, for example in the case of chemicals or high temperatures, then Viton ® (FKM) is an alternative. Possibly also in CR or EPDM.